Oil containment system for emergency use

ABSTRACT

A system and method for containing oil or other contaminants which have leaked from an oil tanker or similar structure is disclosed. A series of flotation members are connected end to end and stored around the perimeter of the tanker. A membrane is folded and packed into a recess in each member and held between the member and the tanker. The members are held against the sides of the tanker by a movable stay. In case of an oil leak, a triggering mechanism sequentially moves the stays to release the flotation members, which drop off the tanker into the water. One edge of the membrane is attached to the members while the opposite edge of the membrane is free. The free edge of the membrane falls from the members so that the membrane forms a curtain in the water. Each flotation member is further connected to adjacent members by a flexible jacket and adjacent edges of each membrane are connected to each other. In this manner, a continuous curtain surrounds the tanker to prevent passage of all or most of the spilled oil. The curtain and/or the tanker may be maneuvered to best contain the spill. The curtain may be detached from the tanker and maneuvered to pinch off and isolate the spill from the tanker.

This application is a continuation-in-part of U.S. Pat. application Ser.No. 07/458,898, filed on Dec. 29, 1989.

FIELD OF THE INVENTION

This invention relates to the field of hazardous materials and moreparticularly to systems for containing spilled contaminants.

BACKGROUND OF THE INVENTION

Leakage of contaminants, particularly oil, from oil tankers, offshoredrilling platforms, or similar structures poses a serious environmentalhazard. Various methods of cleaning up such spills have been devised.However, the longer the clean-up procedures take, the farther the spilltravels from the ship. Consequently, the spill becomes even moredifficult to clean up.

Devices are known to confine the spill to a manageable area. Forexample, oil fences comprising floats with curtains suspended from thefloats have been used. Such a fence generally must be towed by tugboatsuntil the fence surrounds the spill. A disadvantage to this approach isthat time is lost getting the tugboats and the fence to the location ofthe spill.

Another solution has been to carry the fence on the oil tanker itself.However, previous devices of this nature take up room and are difficultto deploy.

SUMMARY OF THE INVENTION

The present invention provides an oil containment system for mounting onoil tankers or the like which takes up little room when stored on thetanker and is easily and rapidly deployable and maneuverable to containa spill as soon as it occurs. In addition, the present oil containmentsystem is readily mountable on the tanker and may be remounted forreuse.

A series of connectable flotation members are stored around theperimeter of the tanker. A membrane is folded and packed into a recessin each member and held between the member and the tanker. One edge ofthe membrane is attached to each flotation member while the oppositeedge of the membrane is free. The members are held against the sides ofthe tanker by a releasable stay. In case of an oil leak, a triggeringmechanism sequentially releases the stays to allow the members to dropoff the tanker into the water. The free edge of the membrane falls fromthe canister so that the membrane forms a curtain in the water. Eachflotation member is further connected to adjacent members by a flexiblejacket and adjacent edges of each membrane are connected to each other.In this manner, a continuous curtain surrounds the tanker to preventpassage of most of the spilled oil. The curtain and/or the tanker may bemaneuvered to best contain the spill. The curtain may be detached fromthe tanker and maneuvered to pinch off and isolate the spill from thetanker.

DESCRIPTION OF THE DRAWINGS

The invention will be more fully understood from the following detaileddescription taken in conjunction with the accompanying drawings inwhich:

FIG. 1 is a side elevational view of an oil tanker illustrating the oilcontainment system of the present invention in its storage position on atanker;

FIG. 2 is a top plan view of the tanker of FIG. 1 illustrating the oilcontainment system of the present invention in its deployed position inthe water;

FIG. 3 is a partial cross-sectional view of the oil containment systemof the present invention in its storage position;

FIG. 4. is a further partial cross-sectional view of the systemillustrated in FIG. 3 in the deployed position;

FIG. 5 is a partial cross-sectional view of the oil containment systemillustrated in FIG. 3;

FIG. 6 is a side elevational view of the system of FIG. 5 with a portioncut away;

FIG. 7 is a cross-sectional view along line VII--VII of FIG. 6;

FIG. 8 is a side elevational view of the system of FIG. 3 in thedeployed position;

FIG. 9 is a side elevational view of a jacket employed in the system ofFIG. 7;

FIG. 10 illustrates a section of the present invention in the storageposition;

FIG. 11 is a cross-sectional view of a securing and triggering mechanismemployed in the system of FIG. 5;

FIG. 12 is a cross-sectional view along line XII--XII of FIG. 11;

FIG. 13 is a plan view along line XIII--XIII of FIG. 11;

FIG. 14 is a plan view of the system of FIG. 3 at the bow of a vessel;

FIG. 15 is a partial cross-sectional view along line XV--XV of FIG. 14;

FIG. 16 is a plan view of the system of FIG. 3 at the stern of a vessel;

FIG. 17 is a plan view of the system in the deployed position;

FIG. 18 is a partial elevational view of a further embodiment of thepresent invention;

FIG. 19 is a further embodiment of the present invention in the storageposition;

FIG. 20 is the embodiment of FIG. 19 in the deployed position;

FIG. 21 is the embodiment of FIG. 19 during mounting into the storageposition;

FIG. 22 is a cross-sectional view of a further embodiment of the presentinvention; and

FIG. 23 is a further embodiment of the present invention;

FIG. 24 is a further embodiment of the present invention;

FIG. 25 is a further embodiment of the present invention;

FIG. 26 is the embodiment of FIG. 25 in the deployed position; and

FIG. 27(a)-(d) illustrate a method of maneuvering the oil containmentsystem of the present invention to isolate a spill.

DETAILED DESCRIPTION OF THE INVENTION

The invention is shown generally at 10 in FIGS. 1 and 2. The inventioncomprises floatable members 16 attached serially to surround an oiltanker 12. In the stored position, the floatable members are mounted tothe sides 14 of the tanker as shown in FIG. 1. The invention is shown inits deployed position by the dotted line in FIG. 2. When deployed,flexible jackets interconnecting the floatable members expand thedistance between each member so that the members are spaced away fromthe sides of the tanker. A membrane is attached to the floatable membersand drops from the floatable members to form a continuous curtain in thewater. In this manner, the invention forms a continuous boundarysurrounding the tanker to contain the oil in the vicinity of the tanker.

The preferred embodiment of the present invention is shown moreparticularly in FIGS. 3-16. The floatable members comprise canisters 30arranged serially end to end, as shown in FIGS. 8 and 10. The canisterspreferably are made of stainless steel for good water and corrosionresistance, although any other suitable material, such as polyvinylchloride, or composites of materials, including a durable coating ofmaterials such as stainless steel or polyvinyl chloride, may be used.

Each canister has a generally triangular cross-sectional shape with tworecessed areas 42, 44 in one face, as shown in FIGS. 3 and 4. The upperrecessed area 42 contains a securing mechanism for securing thecanisters to the tanker and a triggering mechanism for releasing thecanisters from the tanker, to be more fully described below. The lowerrecessed area 44 forms a membrane storage recess, also to be more fullydescribed below.

The canister may be readily formed from plates or sheets of stainlesssteel bent to a suitable shape and joined by welding or any othersuitable manner known in the art to form a water-tight seal. In theembodiment shown in FIG. 5, four plates 33, 35, 37, 39 are used.Internal bracing members 43, 45, 47 may be provided to strengthen thecanisters. Additionally, the plates may include extended elements toprovide further strengthening, such as element 41 of plate 35, andelement 46 of plate 39. Other canister configurations, such as, forexample, the configurations shown in FIGS. 22-24, are contemplated bythe invention

End caps 50, formed to fit the cross-sectional shape of the canister,may be welded or otherwise joined to close off the ends of eachcanister, as shown in FIGS. 6 and 7. Cap 50 preferably includes a lip 52extending around its perimeter to fit against the plates 33, 35, 37, 39.A suitable flotation material 48 such as a closed cell foam, to aid instrengthening the canister and in preventing damage from leakage, ispreferably inserted into the cavity or cavities of each canister formedby the plates and end caps.

Plate 33 preferably extends beyond each end cap 50, as shown in FIG. 7.Gasket 54 provides a seal between adjacent canisters when the canistersare in the storage position. This gasket preferably is securely fastenedto one of the canisters and pulls off the adjacent canister duringdeployment.

Flexible jacket 32 spans the gap between adjacent canisters 30, as shownin FIGS. 7 through 9. The jackets form a continuous barrier betweencanisters when they are deployed. Hooks 60, crimped closed, fasten thejacket to eyes 62 on end caps 50, although the jacket may be fastened inany other suitable manner. Cables 64 are provided within the jacket andextend between the hooks. When the system is stored, the jackets areslack. When deployed, the slack in the jackets is taken up, allowing thedistance between adjacent canisters to increase so that the system maybe spaced away from the tanker to encompass a larger volume ofcontaminant. Cables 64 bear the load exerted by the canisters whendeployed. Each canister may additionally be connected to adjacentcanisters by a short cable link (not shown) as a safety measure.

A membrane 40 is attached to each canister 30 along its upper edge. Acable or chain 70 is generally encased along the bottom edge of themembrane. Preferably, a single sheet of membrane is attached to eachcanister and extends slightly beyond one end of the canister, as shownin FIGS. 8 and 10. Adjacent membrane sheets are fastened along theirvertical edges 72 in any suitable manner. Preferably, the membranesheets are fastened with removable or releasable fasteners.Alternatively, one sheet of membrane may span several canisters beforejoining an adjacent sheet of membrane. Each membrane sheet may have acut away area 76 to accommodate connections between adjacent cables orchains 70. Each membrane sheet is also fastened to each canister in anysuitable manner, such as by fasteners at points 66, 68 as shown in FIG.8. The membrane may be formed from any suitable geotextile known in theart. In an alternative embodiment, each membrane sheet may be integralwith the jacket interconnecting two canisters.

As shown in FIGS. 5 and 10, the membrane 40 is folded up with horizontalfolds for storage within the recessed area 44 and held between canisters30 and the side 14 of the tanker when the canisters are in the storageposition. Since each sheet of membrane is longer than its associatedcanister to allow expansion of the membrane to its full length whendeployed, the extension of the membrane sheet beyond the canister end isfolded with two vertical folds, shown by dotted lines 72, 74 in FIG. 10,to fit compactly within the recessed area 44. If desired, a smallsection of the bottom edge of each membrane sheet may be left free ofthe cable or chain 70 to better accommodate this folding. In thismanner, the stored membrane is readily deployable and protected frombuffeting by waves.

In an alternative embodiment, the membrane 240 may be horizontallyfolded or rolled and inserted into the recessed area 244 with a sinuousor wavy shape, as shown in FIGS. 18 and 22. The recessed area issuitably sized to accommodate this sinuous shape.

When the system is deployed in the water, as shown in FIGS. 4 and 8, themembrane unfolds (or unrolls) and the vertical folds (or sinuous shape)flatten out so that the membrane can surround the tanker at a distancespaced away from the tanker. The canisters 30 float on the surface andthe membrane 40 is suspended from the canisters. Weights (not shown) maybe provided on the bottom edge of the membrane if desired, but theweight of the membrane 40 and the encased cable or chain 70 is generallysufficient, so that such weights are not necessary.

The canisters 30 preferably are mounted slightly below the level of thedeck of the tanker to be as far removed from the buffeting of waves aspracticable. As shown in FIG. 5, angled seating members 90 may be weldedat intermittent locations along both sides 14 of the tanker's hull. Thebottom 92 of each canister 30 rests in these seating members. Theseseating members preferably are spaced so that one seating membersupports the ends of adjacent canisters.

The canisters are secured to the hull by a mechanism mounted within therecessed area 42. As shown in FIGS. 5 and 11, a conduit 102 is fastenedto both sides 14 of the hull somewhat above the seating members 90 andpositioned to fit within recessed area 42 of the canister. Theseconduits run the entire length of the tanker on both sides. A pin 106 isfastened to the side 14 directly below conduit 102 at intervals ofgenerally twice per canister. Cam 108 is pivotally mounted on this pin.Enlarged head 120 of pin 106 and bushings 124, 126 are provided toprevent the cam 108 from slipping on the pin. As shown in FIG. 13, camstays 115 are generally U-shaped brackets having two flanges 131fastened to the canisters by bolts 129. Each cam fits through an opening114 in conduit 102 and an opening 116 in cam stay 115. Openings 114 and116 are vertically aligned with one another. When the cams are insertedthrough these openings, the canisters 30 are held against the tankerhull in the storage position. Face 117 of cam 108 may be beveledslightly to more tightly engage with face 119 of cam stay 115 as the camis rotated into opening 116. Additional bearing members 125, 127 may beprovided to further support the canisters and prevent distortion by wavebuffeting.

The canisters are mounted on the tanker hull by first placing thebottoms 92 into seating members 90. As shown in FIG. 12, a wire 170 isattached to each cam 108 by eye 172. Wire 170 extends through opening116 in cam stay 115 out to the side of the canister. By pulling on wire170, the cam is rotated into position to lock the canister against thehull, as shown by the dotted lines in FIG. 12. A gasket 122 may beprovided along the sides of the hull at the top of the canister tominimize water running between the canister and hull and provide tensionon the assembly to maintain it snugly against the ship.

An alternative embodiment for initially mounting the canister to thevessel is shown in FIG. 22. In this embodiment, cams 250 are rotatedinto position by a tool that reaches through an access port 272 providedin each canister 230. The access port may be protected by a cover 274.

The preferred embodiment of a triggering mechanism employed to deploythe system is shown in FIGS. 11 and 14-16. As shown in FIG. 14, conduit102 extends around the bow of the tanker. Two pistons 130, 132 arecarried in closely spaced alignment inside the conduit 102, one on eachside of the ship. Cables 104, 105 are provided vertically adjacent toeach other inside conduit 102 to surround the hull. Cable 104 isfastened to piston 132 and extends through a hole 134 in piston 130, asshown in FIG. 15. Similarly, cable 105 is fastened to piston 130 andextends through a hole in piston 132.

Conduit 102 extends around the bow of the tanker, as shown in FIG. 16.Motors 140, 142 are provided for pulling cables 104 and 105 respectivelyaround the ship in a circuit. As each cable 104, 105 is pulled around,the piston to which the cable is connected is pulled through conduit102. The piston hits each cam 108 sequentially and rotates the cam sothat the cam is no longer inserted in opening 116 of cam stay 115, asshown by the solid line in FIG. 12. When the cams are in this position,the canisters 30 are no longer secured to the hull of the tanker andtend to fall away from the hull, dropping out of their seatings 90 andinto the water. Leaf springs 136 provide an additional force tending torotate the canisters 30 away from the hull. In this manner, thecanisters are deployed sequentially, beginning at the bow of the tankerand ending at the stern. Specially formed flexible jackets and floatspreferably are provided to cover the bow and stern assemblies andconnections are provided to the port and starboard assemblies.

When the system is deployed in the water, additional cables 150preferably are provided to loosely tether occasional canisters to thetanker, as shown in FIG. 4. These cables allow the deployed barrier tobe maneuvered around the tanker for optimal performance. For example, asshown in FIG. 17, if the spill is discharging a greater amount of oil onone side of the tanker, the tethering cables on the opposite side can bepulled in to allow the barrier to expand on the side of the spill. Also,the tanker itself may be maneuvered so that the barrier expands on theside of the greatest amount of the spill or to place the spill on theleeward side of the tanker. Protective guards (not shown) may beinstalled to prevent propeller fouling.

A further embodiment is shown in FIGS. 19-21. A triangular cover 302 ispivotably mounted to the side 14 of the vessel 12 at hinge 304. Aplurality of such covers 302 extend the length of both sides of thevessel. At the upper end of cover 302 is lip 306. Cover 302 is held inthe storage position by pivotable cam 308. Cam 308 is preferably similarto cam 108 and the triggering mechanism for releasing covers 302 ispreferably similar to that described above. Covers 302 may be overlappedat their edges such that, when sequentially deployed, the first cover tobe released laps over the next cover to be released.

Within cover 302 is contained float canister 314 and membrane 316attached to canister 314. Membrane 316 is packed within storage area 320in a manner similar to that previously described. As shown in FIG. 21,bars 322 removably inserted in tubular sockets or seatings 324 mountedon each end of each canister 314 aid in retaining the folded membrane inarea 320 during mounting. Bars 322 may be removed as covers 302 areclosed against the hull. When the system is deployed, cover 302 dropsdown, as shown by the dotted lines in FIG. 19, and canister 314 andmembrane 316 drop into the water, as shown in FIG. 20. Float canisters314 are preferably connected to one another with jackets such as jacket32 described above.

A further embodiment is shown in FIG. 23. In this embodiment, canister402 comprises sheets 404, 406, 408, which form two cavities 410, 412,which may be filled with a flotation material. Sheet 404 may also have aflat portion 424 to strengthen the canister. Bracing member 414 isprovided on the upper portion of the canister to further strengthen thecanister and reduce the weight. Several such bracing members may beprovided on each canister. Cam stay member 420 and support member 422may be mounted to the bracing members 424. Additionally, membrane 440may be attached to the canister at point 442 near the bottom of thecanister. This canister configuration tends to provide a lower center ofgravity and increased stability in the water.

A further embodiment is shown in FIG. 24. This embodiment is alsoprovided with intermittent bracing members 504 in the upper portion ofcanister 502. The securing and triggering mechanisms, which may be aspreviously described, are contained in area 510 and the membrane 540 iscontained in area 512. Areas 510 and 512 are separated by support member514 attached to the canister and support member 516 attached to thehull.

An additional embodiment, similar to the embodiment of FIGS. 19-21, isshown in FIGS. 25 and 26. The flotation member 614 has a generallytriangular configuration with a recessed area 616 in one face forstorage of membrane 640. The lower portion 618 of flotation member 614is formed to be heavier or of greater density than the upper portion620. The center of gravity of the member 620 is such that when deployedin the water, the member will tend to float in a position slightlytilted from an upright position as shown by the dotted lines of FIG. 26.Any contaminant 630 floating on the water surface 632, as shown in FIG.26, or floating near the water surface, will provide a force tending topush the flotation member into the upright position, as shown by thesolid line in FIG. 26. The recessed area 616 of flotation member 614also further functions as a barrier to contain any contaminant.

The canister embodiments of FIGS. 3-16 and 22-24 also include recessedareas for membrane storage and for housing the securing and triggeringmechanisms, as described above. These recessed areas may also functionas a barrier to contain any contaminants floating on or near the watersurface, as described in connection with the embodiment of FIGS. 25 and26. Additionally, the floatable canister may be configured with itscenter of gravity such that the canister tends to float in a positionslightly tilted from an upright position and any contaminant floating onor near the water surface will tend to force the canister into a moreupright position, as described in connection with embodiment of FIGS. 25and 26.

Once the barrier is deployed surrounding the tanker, the movement of thespill is ascertained to determine the optimal method of containing thespill. For example, the barrier may be left in position completelysurrounding the tanker and the barrier's position and orientation in thewater may be controlled by tethers attached to the tanker, as shown inFIG. 17, or by movements of the tanker itself. In this manner, forexample, the barrier may be guided to balloon out on the side of thespill to encompass a great volume of material without forcing thecontaminant around the sides of the tanker. The tanker may be allowed todrift, may be anchored, or may be moved and steered, depending onconditions.

Additionally, the barrier may be detached from the tanker and guided topinch off and isolate the spill or sections of the spill from thetanker, as shown in FIGS. 27(a)-(d). This action is desirable if thespill has stopped or if additional containment systems or devices of anynature are available for further containment or clean up of the spill.Such isolation of the spill is also desirable if the spill is flammableor otherwise poses a hazard to the tanker personnel.

In FIG. 27(a), the barrier 710 completely surrounds the tanker 712 andthe spill 714 is discharging from one side of the tanker. In FIG. 27(b),the barrier is broken open to form two ends 716, 718. One end 718 isattached to the tanker, either directly or with a tether 720. A smallboat 722 captures the other end 716 so that it may be maneuvered aroundthe tanker 712. The captured end is maneuvered around the tankeropposite the side from which the spill 714 is discharging. Thismaneuvering may be done by moving the small boat 722, by movements ofthe tanker 712, or a combination of both. Additionally, the small boat722 may be remotely controlled if desired. As shown in FIG. 27(c), theboat 722 brings the captured end 716 of the barrier 710 around to theside on which the spill 714 is located, and the spill is maneuvered awayfrom the tanker, either by naturally drifting away or by moving thetanker 712. The boat 722 with the captured end 716 of the barrier 710pinches off the spill 714 to enclose it entirely within the barrier 710,as shown in FIG. 27(d). If the discharge of the spill from the tankerpreviously has been halted, the spill may be allowed to separate fromthe tanker before being encircled by the barrier as in FIG. 27(d). Theencircled and isolated spill may then be marked with flags or othersignaling devices for subsequent location and identification.

The invention has been described in relation to an oil tanker. However,the oil containment system of the present invention may be used withother structures, such as an offshore oil drilling platform, or any fuelpowered vessel where the danger of contaminants leaking into waterexists.

The invention is not to be limited by what has been particularly shownand described, except as indicated by the appended claims.

I claim:
 1. A method for containing a contaminant spill leaking from aship into water, comprising:providing a barrier in a storage positionaround the perimeter of the ship; deploying the barrier into the waterto form a continuous loop surrounding the ship; breaking the continuousbarrier at a point to form a first end and a second end; and maneuveringthe first end of the barrier around the ship to rejoin the second end ofthe barrier with the contaminant contained within the barrier.
 2. Themethod of claim 1 including attaching the second end of the barrier tothe ship after breaking the barrier to form the first and second ends.3. The method of claim 1 including attaching the barrier to the shipwith a tether.
 4. The method of claim 3 wherein the barrier is attachedto the ship with the tether after the first and second ends arerejoined.
 5. The method of claim 1 including marking the barrier withmeans for signalling after the first and second ends ar rejoined.
 6. Themethod of claim 5 wherein the signalling means comprises a flag.
 7. Themethod of claim 1 wherein a boat captures the first end of the barrierand maneuvers the first end around the ship.
 8. The method of claim 7wherein maneuvering the first end of the barrier around the shipincludes moving the ship.
 9. The method of claim 7 wherein the boat isremotely controlled.
 10. A method for deploying an oil containment boomto surround a contaminant leaking from a structure into water,comprising:storing a continuous, impermeable barrier around theperimeter of the ship, the barrier comprising a plurality of flotationmembers connected end to end, a membrane attached along an edge to theflotation members to depend from the flotation members to form acontinuous curtain surrounding the structure when the barrier isdeployed in the water, and means for releasably storing the flotationmembers and the membrane around the perimeter of the structure; anddeploying the barrier into the water to form a continuous loop in thewater surrounding the structure by sequentially releasing each flotationmember from the structure beginning at a first point and progressingsequentially along the barrier in opposite directions.
 11. The method ofclaim 10 further including:breaking the continuous barrier at a point toform a first end and a second end; and maneuvering the first end of thebarrier around the structure to rejoin the second end of the barrierwith the contaminant contained within the barrier.
 12. The method ofclaim 10 further including ballooning the barrier out on one side of thestructure to contain a discharge of contaminant from the one side of thestructure.
 13. The method of claim 10 further including attachingtethers from the structure to the barrier and manipulating the tethersto maneuver the barrier.
 14. The method of claim 10 wherein thestructure is a ship.